Clamping mechanism for metal-working machines



May s,` l1923. 1,454,080

W. T. SEARS CLAMPING MECHANISM FOR METAL WORKING MACHINES y F'il'e'd June 16.I 1920 2 Sheets-Sheet l 11 A b 11 y a 12 16 a 9 f 121921. e 16 f 1o 1" 1o f ,.l. m 22 im 2 o Y ed 30 lI 'li 2 fwz l.-- 33 i l I I l l a lili i l|l Hl,

j n /Y o d 1 o W. T. SEARS CLAMPING MECHANISM FOR'METAL WORKING MACHINES May 8, 1923.

Fiied June .16, 2 sheets-sheet 2 if' .anon no" aronanon or Applikation mee aune'iaiaao.' semina. 389,425;

To all whom it may concern.

Be it known that I, WILLARn T. Snare, aV

- citizen of the United' States, .residing at Montclair, in the county of Essex and State of New Jersey, have invented 'certain new and useful Im rovements 'in Clamping. `Mechanism .for

etal-WorkingY Machines,

- of which the following is a specication.

This invention relates to metal working machines and particularly to machines of the e wherein a cutter-supporting rail is vertically adjustably mounted on an upright or uprights adjacent the work table of thema'-l chine. More specifically the invention is particular] applicable to vertical boring mills and p aners, and one object ofthe invention is the provisin of an improved clamping mechanism for securing the rail tothe 'uprights, such improvement preferably,

though not necessarily, taking-the form Vof a rotary clamping motor or motors mounted on the cutter-supporting rail.

`- Another object of the invention resides in providing an interlocking mechanism for preventing the throwing-in' of the rail elevating and lowering mechanism while the rail is in the clamped position. rIhis mechanism may consist of an interlock between the controlling element of the rail vmoving means and the controlling element of t e clamping means, of an' interlock between the controlling element of the rail moving means and vthe clamp itself, or of a combination of both theseA mechanisms.

' Another object of the invention is to provide an interlocking mechanism between the controlling 'means for .the rail moving mechanism and the controlling'means for the clamping mechanism whereby simultaneous operation .of such two controlling means is prevented, and lwhich interlocking mecha-K nism furthermore permits the operation of lso the first or second mentioned controllingmeans only when the second or rst mentioned controlling means respectively is in the unclamped and inoperative positions respectively.

" l It is another object of the invention to provide a clampingmechanismoperated by power means, preferably comprising electric i motor means mounted on the rail, such construction also preferably providing an interl locking mechanism between vthe controlling switch for the clamping motor or motors anda controlling lever for therail moving means whereby the operation ofthe lever or switch -is permitted only when the switch or lever respectively is in the unclampingv and inoperative positions respectively.

A further object ofthe inventionresides' in the provision of the above second mentioned interlocking mechanism' between the` controlling element of the rail moving means and therail clamp itself whereby the operation of the rail moving means 1s positively prevented until the clamp is4 released from clamping engagement witho the rail..

YUndernormal conditions,- the first interlocking mechanism above defined is ample to prevent any strain or breakage of the machine due to the rail moving mechanism being thrown into operation while the rail is in clamped position. .However, shouldsome of the mechanism fail to function, it 'is `possible that such ka breakav e might occur. it

is therefore a further object Aof the invention to provide a double interlocking mechanism whereby such an occurrence is ositivelyprevented, such mechanism pre erably taking the form of`a combination of the twointerlocking` mechanisms above defined whereby the. rail moving vmeans is positively prevented from 'operation until the clamp is releaed from clamping engagement with the rai as'the description proceeds.

Referrin'g'tol the figures of the drawings.: Figureil is a rear perspective view o a boring mill illustrating the present invention.

on the line 2-2 of Fig. 1, certain parts being v omitted. i f

Fig. 3 is adetail side`elevation of the controlling lever and switch and the interlocking mechanism therebetween.

Fig. 4 is a front view thereof taken on the line of Fig. I

Fig. 5 is a plan view thereof,the switch handle being shownv in a dierent position.l

Fig. 6 isa-sectional view through the gear box showing'the gearing for driving the rail elevating and lowering mechanism..

Fig. 7 is a sectional'view through one of the clamp yoperating screws taken on the lineV Other objects of the invention will appear Fig. 2 is a horizontal section thereof taken 7e? of Fig. 2,' and yillustrating the frictional driving connection therefor.

Fig. Slis a detail cross sectional -view taken on the'line 8.- 8ofFig. 7 and illustrating the 110' engagement of a clamping arm with its operating nut.

-Figs. 9 and 10 are fragmentary' enlarged sectional views of the machine corresponding to Figs. 2 and 3 respectively,rbut showing a second interlocking mechanism for positively preventing the operatlon of 'the rail moving means until the clamping mechanism is released from clamping enage of such operating parts .of the machine` is to be positively prevented. Such a mecha-` nism may be em odied in several forms, certain of which are herein disclosed, all of such mechanisms being of such construction that the simultaneous operation of the rail moving means and the clamping means, to move the rail vertically and to clamp the rail to its support respectively, is positively prevented.

In the drawings, l have illustrated my invention as applied to a vertical boring mill although it will be readily understood that the invention is not so limited since it may with equal facility be applied to other machines either having a single upright, as, for example, an open slde planer, or having two uprights as in ordinary planers and like machines.y Also while I have illustrated the interlocking mechanism as combined with a particular form of clamping means it will be understood that. such mechanism is adaptedv to operate as readily with other forms of clamping means. Other details of the invention may be modified within thescope of the claims appended hereto.

Referring to the drawings, 1 represents the base of a boring mill having the uprights 2. and 3 preferably adjustably mounted thereon, as illustrated. A cutter-supporting rail 4 is vertically adjustably mounted on the guides 2a and 3a of the uprights and a saddle 5 supporting a tool holder 5a is movable horizontally along the rail. The rail is moved on the uprights and the saddle is moved on the rail by means of a motor 6 and the connections illustrated in Fig. 1. The saddle and its operating mechanism are not within themselves a part of the present invention and therefore will not be further described herein.

The rail elevating and lowering means preferably comprises the screws 7 and 8 driven from the motor 6 as above stated. Each screw is mounted against longitudinal movement within its upright and is in threaded engagement with projections 7n and 8 respectively71 on the rail. The connecting means between the motor and screws for rotating the latter in either directionis illustrated in Figs. y1 and 6. This mechanism comprises a shaft 9 havin bevel gears 10 and 11 at'the opposite en s thereof in driving engagement with bevel gears 10a and 11u keyed to the screws 7 and 8 respectively. This shaft extends through the gear box 12 and has splined thereto a double toothed clutch element 13 adapted to be engaged with the clutch teeth of either of the two gears 14 and 15. These gears are driven from the motor through the gear 6a on the motor shaft engaging a gear 16a on a shaft 16, a gear 16b on the shaft -16 engaging a gear 17a on a shaft 17, and gears 18 and 19 on the shaft 17 to the gears 14 and 15 loose on the shaft 9. It will be noted that an idler gear 19a is interposed between the gears 15 and 19 whereby the gear 15 is rotated in a direction opposite to that of the gear 14. It will now be seen that the shaft 9, and therefor@ the screws 7 and 8, may be rotated in either direction by engaging the clutch element 13 with one or the other of the gears 14 and 15. The clutch is operated by means of an arm 20 mounted on a rocker shaft 21 and engaging a peripheral groove in the element 13. An arm 22 secured to theshaft 21 is connected to an operating means, as a lever 23, through linkage comprising rods 24 and 25 engaging the arm 22 and lever 23 respectively, the other ends of such rods being operatively connected by a bell crank 26 pivoted to the frame of the machine. It will be seen that the lever 23 is pivoted at 23a and that vertical movement thereof in one direction or the other will cause the rail moving screws `to be ope-rated in either a right or left hand direction and thus elevate or lower the rail 4 on the uprights.

The rail clamping lmeans is preferably l mounted on the rail and, as illustrated. comprises an yelement 27 pivoted to the rail adjacent each upright. The short arm 27n of each element 27 is adapted to clampingly engage its upright and the long arm 27h thereof is preferably engaged by a nut 28 mounted on a clamping screw 29 journaled in the machine frame at 29a. As shown in Fig. 8 the arm 27b non-rotatably engages the nut 28y and the nut may be made in one or two pieces as illustrated. Rotation of the screw in one direction or the other is adapted to move the element to a clamping or unclampillustrated at 30 in Figs. 1 and 2, or a separate motor for each clamp, as illustrated at 30 and 30 in Fig. 11. The connection between each screw and the motor preferably com rises a worm 31 and a worm wheel 31a, the atter being mounted on the screw and the former being driven from the motor. Such a connection prevents the reaction 'of the clamping means in its clamping position fromrotating the motor in an unclamping direction even though the electric current to the motor is cut off. When using a separate motor for each clamp, the worm wheel may be keyed directly to its screw. 29. However in order. to be sure that both clamping elements are in tight clamping engagement with their uprights, when using a single motor for both clamps, it is necessary to yprovide a special connection between the motor and such elements. As a convenient means for performing this function, l frictionally mount each worm wheel 31* on its screw between two friction plates 32 and 33, as illustrated in Fig. 7. The plate 32 is secured rigidly or integrally to the screw and the plate 33 is splined for longitudinal movement thereon. A spring 34 adjustable by means of the nut 34a threaded onto the screw serves to hold the plate 33 in frictional contact with the worm wheel. By this construction it will be seen that when either of the clamps is seated to clamping position, its worm wheel slips as the motor continues to run whereby the other clamp is brought up to to a like clamping position before any v slipping thereof takes place. The nuts 34a may bevadjusted to bring the two springs 34 under an equal compression whereby both clamps will bind with an equal pressure. The rail moving means is preferably controlled by a hand lever 23 heretofore described and the motor is controlled by la switch 35, these elements and their cooperating parts being illustrated in Figs. 3, 4,*and 5. The switch 35 comprises a handle 35 and two contact knives 36'and37 adapted to engage the poles 36 and 37 a res ectively. The contact of the knife 36 and po e 36a isadapted to rotate the motor in an unclamping direction and thecontact of the knife 37 and pole 37 is adapted to rotate the motor in its clamping direction. The interlocking means between the lever and switch as herein illustrated comprises a plate 38 secured to the v.switch handle 35a and having a slot 39 therein adapted to cooperate with the lever. This slot as shown is T-shaped and the lever extends through the slot in such manner as to permit the lever to be moved vertically only when the switch is in the unclamping position, illustrated vin-Fig. 5. It will be seen that'when the switch is in any other position than the unclamping position the lever is in the horizontal portion 39a of rthey slot `which position corresponds to the' neutral switch is in the unclamping'positon and the lever is in the vertical portion 39" of the slot 39 above or below the horizontal portion 39 the switch' is lockedfrom movement from the unclamping position. yIn this manner'` the plate serves as an interlocking mechanism positively preventing the engagement of the clutch 13 except when the .switch is in' an unclamping position andv prevents a clamping contact of they switch' while the clutch is in other than a neutral position.

Under'normal conditions the interlocking mechanism between the lever 23 and the switch handle 35a as just described is fully ample to protect the machine from any breakage due to the throwing-in of 'the clutch 13 while the rail is in a clamped position. However, if for any. reason the motor or its cooperating mechanism should fail. to function it is possible that such a breakage might occur. As a means to positively prevent the throwing-in of the 'clutch 13 and therefore the operation of the rail moving mechanism while the rail is clamped, I provide another -form of interlockiny nism shownv in Figs. 9 and 10. It s ould be mchaunderstood that'this construction may be ,4

42a and between two collars 43 and 43a on f the rod 25. A spring 44 mounted within the solenoid serves to keep the projection' nor.- mally in its outward position and in engagement with the rod 25 between the collars. vThe terminals of the coil of the solenoid are connected to a contact 45 on one of the clamping arms, as illustrated in Fig. 9, and to a spring 46 on theframe'extending to a position adjacent the contact 45. By this construction the rod v25, and therefore the clutch 13, is positively locked in its neutral position until the clamping arm 27 comes to an unclamping posit-ion whereupon the contacts 45 and 46 engage and the lock- 'ing member 42 is drawn from engagement lll) the last described interlock positively prevents the throwing-in ofthe clutch until the clamping means 'is in its unclamped position and the interlock between 'the lever 23 and the switch handle 35a prevents the movement of the switch to its clamping position until the lever and clutch have again been brought back to neutral position.

What I claim is:

1. lin a machine of the class described, the combination of 'a base, a work table mounted thereon, an upright adjacent the table, a cross rail mounted to slide vertically on the upright, means to move the rail vertically, clamping means on the rail for securing the rail to the upright, and a rotary electric motor on the rail for operating the clamping means.

2. In a machine of the class described, the

combination of a base, a work table mounted thereon, an upright adjacent the table, a-

cross rail mounted to slide vertically on the upright, means to move the rail vertically, clamping means on the rail for securing the rail to the upright, a rotary` electric motor for operating the clamping means, and a driving connection between thel motor and the clamping means so constructed that in its clamping position the reaction of the clamping means cannot rotate the motor in an unclamping direction even though the electric current tothe motor is cut off.

3. In a machine of the class described,the combination of a base, a work table mounted thereon, two uprights adjacent the table, a cross rail mounted to slide vertically on the uprights, means to move the rail vertically,

clamping means on the rail adapted to en gage both uprights to secure the rail thereto,

' and lrotary electric motor means for operating the clamping means.

4. 'In a machine of the class described, the

' combination of a base, a work table mounted thereon, two uprights adjacent the table, a cross rail mounted to slide'vertically on the uprights, means to move the rail vertically,

clamping means on the rail adapted to engage both uprights to secure the rail thereto, rotary electric motor means on the rail foroperating the clamping means, and a driving connection between the motor means j and the clamping means so constructed that in its clamping position the reaction of the clamping means cannot rotate the motor means in an unclamping direction even though the electric current to the motor means is cut ofi'.

5. ln a machine of the class described, the

, combination o a. base, a work table mounted Can Vconnected to the arms for operating the same.

6. Ina machine of the class described, the combination of a base, a work table mounted thereon, two uprights adjacent the table, a cross rail mounted to slide vertically on the uprights, means to move the rail vertically, a clamping means on the rail adjacent each upright, each clamping means being adapted to engage its upright to secure the rail thereto, a,rotary electric motor on the rail, and a frictional connection between the motor and each of the clamping means.

7 In a machine of the class described, the combination of a base, a Work table mounted thereon, two uprights adjacent the table, a cross `rail mounted to slide vertically on the uprights, means to move the rail vertically, a clan'ipilig means on the rail adjacent each upright, each clamping means being adapted to engage its upright to secure the rail thereto, a rotary electric motor on the rail, and a frictional connection between the motor and each of the clamping means, such connection comprising two worms driven by the motor and engaging two worm wheels respectively on the clamping means.

S. In a machine of the class described, the combination of a base, a work table mounted thereon, an upright adjacent the table, a vertical guideway on one side of the upright, a cross rail mounted to slide vertically on the guideway, power means to move the.

rail vertically, clamping means for securing the rail against vertical movement on the guideway, rotary power means for operating the clamping means, and an interlocking mechanism permitting the operation of the rail moving meansvonly when the clamping means is in its inoperative position.

9. ln a machine of the class described, the combination of a base, a work table mounted thereon, an upright adjacent' the table, a

vertical guideway on one side of the upright, a cross rail mounted to slide vertically on the guideway, power means to move the 4rail vertically, clamping means on the rail for securing the rail against vertical movement on the guideway, rotary power means for operating the clamping means, and an interlocking mechanism permitting the opf eration of either the rail moving means or the clamping means only when the other of the said two means is in its unclamped and 'inoperative positions respectively.

10. In a. machine of the class described, the combination of a base, a work table mounted thereon,l an upright adjacent the table, across rail mounted to slide vertically on the upright, power means to move the rail vertically,y an element forV controlling the operation ofthe power means, clamping means on the rail for securing the rail to the upright, power means for operating the clamping means, an element for controlling the last named power means, and an interlocking mechanism permitting the operation ot' either the first or second element only when the other elementis in the -unclamping and inoperative positions ectively."

11. In a machine of t e class'described, the4 combination of a base, Aa work table mounted thereon, an upright adjacent the table, a cross rail mounted to slide vertically on the u right, means to move the rail vertically, c amping means on the rail for securing the rail to the u right, an electric motor for operating the c amping means, and an interlocking mechanism permitting the operation of the rail moving means only when the .clamping means inits inoperative position. v

Y12. In a machine of the class described, the combination of a base, a work table mounted thereon, an upright adjacent the table, a cross rail mounted to slide verticallyy on the upright, means to move the'rail vertically, a lever for controlling the operation of the rail moving means, clamping means on the rail for securing the rail to the u right, an electric motor for operating t e clamping means, a switch for controlling the motor, and an interlocking mechanism permittin the o eration of either the lever 0r the switch on y when the switch or the leverl respectivelyis4 in the unclamping and inoperative positions respectively.

13. In \a machine of the class described, the combination of a base, a work table mounted thereon, an upright adjacent the table, a cross rail mounted to slide vertically on the u right, means to move the rail vertically, c amping means on the rail fo'rsecuring the rail to the upright, an electric motor on the rail for operating the clamping means. a switch for controlling the motor, a driving connection between the motor and the clamping means comprising a worm wheel on the clamping means engaged by a worm driven from the motor, and an interlocking mechanism permitting the o eration of the rail moving means only w en the `switch is in a clamp releasing position.l

14. In a machine of the class described,`

the combination .of a` base, a work table mounted thereon, two uprights adjacent the table, a cross rail mounted to slide vertically on the uprights, power means to move the rail vertically, clamping means for securing the rail toboth uprights, power means Jfor operating thc clamping means and an 1nterlockin mechanism permitting the opera- :tion of either of the said power means only when the other erative position.

15. In a machine of the class descrlbed,

power means is in its inop- ,the combination of a base, a` work table mountedthereon, two uprights adjacent the table, a cross rail mountedto slide verticall onthe uprights, -wer means toV move the-railjvertieally, c am ing means on the lrail'fforl securing, the ra to -both uprights,

power means on the rail for .operating the operating the clamping means, and an interlocking mechanismy preventing the operation of the rail moving means until the electric current has. been turned on-the motor for releasing the clampin means and preventing a clamping contact o the current during the operation of the rail moving means. 4 17.` In a machine of the class described, the vcombination of a base, a work table mounted thereon, two uprights adjacent the table', a cross rail mounted to slide vertically on the uprights, means to move the rail vertically, clamping means on the rail for securing the rail to the uprights, motor means mounted on the rail for operating the clamping means, and an v interlocking mechanism permittin the operation of the rail moving means on y when -the clamping means is in its inoperative position.

18. .In a machine of the class described, the combination of a base, a work table mounted thereon, two uprights adjacent the table, a cross rail mounted to slide vertically on the uprights, means to'move the rail.'

vertically, clamping means on the rail for securing the rail to one of the uprights,

an electric motor mounted on the rail, a

driving connection between the motorv and the clamping means so constructed that inits clamping position the reaction of the.

clamping means cannot rotate the motor in an unclamping direction even though the electric current to the motor is-cut oil', and an interlocking mechanism permitting the operation' of the rail moving mean s pnly when the clamping means is in its inopera tiveA position.

19. In a machine, of'the class ',descriloed,l the combination of a base, a work. table mounted thereon, two uprights adjacent,"

the table, a cross rail mounted to slide vertically on the uprights, means to move,

,120' rail for securing the rai .to one of then' -f rights, an electric motor mounted' on t ef rail, a driving-connection between the motor the rail vertically, clam ing means o n the and the clamping means comprising a Worm wheel on the 4clamping means engaged by a worm ldriven fromthe motor; and an interlocking mechanism permitting theop-4 4eration of the rail moving means' only when the clamplng means is ,1n its inoperative position.

vertically, c amping means on the rail for securing the rail to the uprights, a single electric motor tor operating the clamping means, and an interlocking mechanism permitting the operation of either of the said v means only when the other means is in its inoperative position.

21. lln a machine of the class described, the combination of a base, a work table mounted thereon, two uprightsadjacent lthe table, a cross rail mounted to slide vertically on the uprights, means to move the rail vertically, clamping means on the railadjacent each upright, each clamping means being adapted to engage its upright to secure the rail thereto, an electric motor mounted on the rail, a frictional connection between the 'motor and each clamping means, and an interlocking mechanism permitting the operation of the rail moving means only when the clamping means is in its inoperative position.

22. ln a machine of the class described, the .combination of a base, a work table mounted thereon, two uprights adjacent the table, a cross rail mounted to slide vertically on the uprights, means to move the rail vertically, clamping means on the rail adj acent each upright, each clamping means being adapted to engage its upright to secure the rail thereto, an electric motor mounted on the rail, a frictional connection between the motor' and each clamping means, such convnection comprising two worms driven by the motor and engaging two worm wheels frictionally secured to the clamping means l respectively, and an interlocking mechanism 'permitting the operation of either of the said means only when the other means is in its inoperative position.

23. In a machine of the class described, the combination' of a base, a work table mounted thereon, two uprights adjacent thevertically, a c amping arm pivoted on the rail adjacent leach upright, one end of each arm being adapted to engage its upright to secure the rail thereto, operating means engaging the other end of each arm, a single electric motor for operating both clamping arms, an interlocking mechanism permit- Ating the operation of the rail moving means only when the clamping means is in its inoperative position. l

24. In a machine ofthe class described, the combination of a base, a work table mounted thereon, two uprights adjacent the: table, a guideway on .one side of each upright a cross railmounted to slide vertically on the insane@ guideways, power means to move the' rail vertically, a lever for controlling the rotation ot' the power means in either direction, clampingo means on the rail adapted to engage both uprights to secure the rail thereto, rotary power means for operating the clamping means, a handle for controlling the last named power means, and an interlocking mechanism permitting the operation of either the lever or the handle only when the 'handle or lever respectively isin the unclamping and` inoperative positions respectively.

the switch has been thrown to a clamp-releasing position.

26. ln a machine lof the class described, the combination of a base, a Work table mounted thereon, two uprights adjacent the table, a cross rail mounted to slide vertically on the uprights, screw means to move the rail vertically, `a lever for controlling the rotation of the screw means in either direction, clamping means on the rail adapted to engage both uprights to secure the rail thereto,

electric motor means on the rail for operatingL the clamping meansa switch for controlling the motor means, and an interlocking mechanism permitting the 'operation of` either the lever or the switch only when the' switch or lever respectively is in the unclamping and inoperative positions respectively.

27.1n a machine of the class described, the combination of' a base, a work table mounted thereon, two uprights adjacent the table, a cross rail mounted to slide vertically on the uprights, screw means to move the rail vertically. mechanism comprising a clutch for operating the screw means in either (direction, a lever for controlling the clutch, clamping means on the rail adapted to engage both uprights to secure the rail thereto, power means for operating the clamping means, a handle for controlling vvthe power means, and an interlocking mechavthe combination ot a base,- a work tableY mounted thereon, two uprights. adjacent the table,

v table,

Y 1,454,0so

a cross rail mounted to slide vertically on the uprights, screw means to move the rail verticall a lever4 for controlling the rotation of t e screw means in either direction, clamping means on the rail adaptved to'engage the uprights to secure the rail thereto, electric motor means for operating the clamping means, and a switch f or controlling the motor means comprising a handle having means thereon for engaging the lever in such manner as to permit the o ration of either the switch or lever only w enz the lever or switch respectively is in the neutral and clamp releasing positions respectively but reventing the simultaneous operation of bot 29. In a machine of the class described, the combination .of a base, a wprk table mounted thereon, two uprights'ad1acent the table, a cross rail mounted to slide vertically on the upii hts, screw means to move the rail vertically, a' lever for controlling the rotation of the screw means in either direc-- tion, clampin means on the rail adapted to engage one o the uprights to secure the rail thereto, an electric motor f or operating the clamping means, anda switch for controlling tlie motor comprising a plate having a T-slot therein, the lever extending through such slot in such manner that the lever is locked from movement except when the switch is thrown to a clamp releasing position.

30. In a machine of the class described, the combination of a base, a work table mounted thereon, an upright adjacent. the a cross rail mounted to slide vertically on the upright, means to move the rail vertically, an element for controlling the operation of the rail-.moving means, clamping means on the rail for. securin the rail to the upright, an electric motor or operating the clamping means, and a positive interlocking mechanism permitting the o eration of the said element only when the c amping means is disenga d.

31. In a machine of the class described, the combination of a base, a Work table mounted thereon, two uprights adjacent the table, a cross rail mounted to slide vertically on the upri hts, means to move the rail vertically, an e ement for controlling the operation of the rail moving means, clamping means on the rail for securing the rail to both uprights, rotary power means for operatingvthe clamping means, and a positive interlocking mechanism permitting the operation of the said element only when the clamping means is disengaged..

32. In a machine of the class described, the combination 4of a base, a work table mounted thereon, an upright adjacent the table, a cross rail mounted to slide vertically on the upright, means to move the .rail vertically, an element for controlling the operation of the rail moving means, clamping means on the rail for securing the rail to the upright, power means for operating the clamping means, and an interlocking mechanism includin a solenoid having means controlled there y and adapted to positively engage and secure the said element from operation when the clamping means is in the clamped position, the clamping means in its unclamped position being adapted to make an electric contact energizing the solenoid whereb the securing means controlled thereby is isengaged from the said controllin element.

33. n a machine of the class described, the combination of a base, a work table mounted thereon, an upright adjacent the table, a cross rail mounted to slide vertically on the upright, means to move the rail, vertically, an e ement for controlling the operation of the rail moving means, a clampin arm pivoted to the rail for securing the rai to the upright, power means for operating the clamping arm, and an interlocking mechanism, 'including a solenoid having means controlled thereby and'adapted to positivelyl engage and secure the said element from operation when the clamping arm is in the clamped position, the clamping arm in its unclamped position being adapted to make an electric contact energizing the solenoid whereby the securing means controlled thereby is disengaged from the said'controlling element.

34,. In a lmachine of the class described, the combination of a base, a work table mounted thereon, an upright adjacent the.

table, across rail mounted to slide vertically on the upright, means to move the rail vertically, an element for controlling the operation of such means in either direction, clamping means for securingthe rail to the upright, a second element for controlling the clamping means, an interlocking mechanism permitting the operation of either the Iirst or second element only when the second or first element respectively is in the unclamped and inoperative positions respectively, and other interlocking mechanism positively preventing the operation of the first element until the clamping means is inthe uiriclamped position.

35. In a machine of the combination of a base, a work table mounted thereon, kan upright adjacent the table, a cross rail mounted4 to slide vertically on the upright, means to move the rail vertically, an element for controlling the operation of` such .means in either direction, clamping means on the rail for securing the rail tothe upright, an electricmotor for operating the clamping means, a switch for controlling the motor, an interlocking mechanism'permitting the operation of either the l element or the switch only when the switch the class hdescribed, l

Athe solenoid which is energized through an electric contact made by the clamping means in its unclamped position.

36. In a machine'of the-class described, the combination of a base, a work table mounted thereon, two u'prights adjacent the table, a cross rail mounted to slide vertically on the uprights, means to move the rail vertically, an element for controlling the operation of such means in either direction, clamping means for securing the rail to the uprights, a second element for controlling the clamping means, an interlocking mechanisrn permitting the operation of either the first orsecond element only when the second or first element respectively is in the unclamped and inoperative positions respectively, and other interlocking mechanism positively preventing the operation of the first element until the clamping means is in the unclamped position.

37. In a machine of the class described, the combination of a base, a Work table mounted thereon, two uprights adjacent the table, across rail mounted to slide vertically on the uprights, means to move the rail vertically, an element for controlling the operao tion of such means in either direction, clamp ing means on the rail for securing the` rail to thezuprights. an electric motor for operating the clamping means, a switch for conmettete trolling the motor, and interlocking mechanism permitting the operation of either the element or the switch only when the switch or element respectively is in the unclam ing and inoperative positions respective y,

unclamped position.

. 38. ln a machine of the class described,

the combination `of a base, a work table lmounted thereon, two uprights adjacent lthe table, a cross rail mounted to slide vertically on the uprights, means tol move the rail verl tically, an element for controlling` the operation o such means in either direction, a clamping arm pivoted to the rail adjacent each upright, one end of each arm being adapted to engage its upright to' secure the rail thereto, operating means engaginfv the other end of eacn arm, a second element for controlling the arm operating means, an interlocking mechanism permitting the operation of either the first or second element only when the second or first element respectively isin the unclamping and inoperative positions respectively, and other interlocking mechanism positively preventing the operation of the first element until the clamping means yis in the unclamped position. v

ln testimony whereof, I hereto ax my signature. ,l

' WlLLARD T. SEARS. 

